CN109574619B

CN109574619B - Preparation method of magnesium phosphate foamed cement

Info

Publication number: CN109574619B
Application number: CN201811449709.4A
Authority: CN
Inventors: 高育欣; 王硕; 孔亚宁; 程宝军; 毕耀; 麻鹏飞; 陈全滨; 王军
Original assignee: Zhongjian Material Technology Research Chengdu Co ltd; China West Construction Group Co Ltd
Current assignee: China West Construction Group Co Ltd; Building Materials Science Research Institute Co Ltd of China West Construction Group Co Ltd
Priority date: 2018-11-29
Filing date: 2018-11-29
Publication date: 2021-04-02
Anticipated expiration: 2038-11-29
Also published as: CN109574619A

Abstract

The invention discloses a preparation method of magnesium phosphate foamed cement, which comprises the following steps: s1, preparing a ferric chloride solution; s2, adding the ferric chloride solution and borax into a certain amount of water to obtain a mixed solution; s3, uniformly mixing heavy magnesium oxide and dihydric phosphate powder, adding the mixed solution prepared in the step S2 into the mixed powder, rapidly adding hydrogen peroxide, uniformly stirring, and pouring into a test mold; and S4, molding. The raw material components are as follows in parts by weight: 35-45 parts of heavy magnesium oxide, 25-30 parts of monopotassium phosphate, 2-3 parts of borax, 7-30 parts of hydrogen peroxide, 2-20 parts of water and 2-3 parts of ferric chloride solution. The method adopts the heavy magnesium oxide to replace the conventional heavy-burned magnesium oxide as the raw material to prepare the magnesium phosphate foamed cement, solves the technical defect that the magnesium phosphate foamed cement is difficult to prepare by adopting the heavy magnesium oxide in the prior art, reduces the energy consumption, saves the cost, and has good stability.

Description

Preparation method of magnesium phosphate foamed cement

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to a process method for preparing magnesium phosphate foamed cement with certain strength and low density.

Background

The magnesium phosphate cement is mainly prepared from magnesium oxide, phosphate and a retarder according to a certain proportion. The magnesium phosphate cement has the advantages of fast setting, high early strength, strong bonding force, small drying, wear resistance, freezing resistance and the like, and is a novel gel material with great research value, energy conservation and environmental protection. Compared with cement-based materials, the magnesium phosphate cement material has outstanding high-temperature resistance. The magnesium phosphate foaming cement has good heat preservation, heat insulation and high temperature resistance, has small density, and is often used for light wall building blocks, wallboards and the like. At present, the magnesium phosphate foaming process generally adopts dead burned magnesium oxide as a raw material, the dead burned magnesium oxide is formed by calcining magnesite at a high temperature of about 1700 ℃, and the high-temperature calcination energy consumption is large, so that the defects of large cement production energy consumption, high economic cost and the like exist. The production process of the heavy magnesium oxide does not need high-temperature calcination, and the energy consumption is less, so the price is low. However, prior art studies have shown that heavy magnesium oxide sets too quickly and cannot be used as a raw material for the production of magnesium phosphate foamed cement.

Disclosure of Invention

The invention aims to overcome the technical defect that magnesium phosphate foamed cement is difficult to prepare by using heavy magnesium oxide as a raw material in the prior art, and provides a novel method for preparing magnesium phosphate foamed cement by using heavy magnesium oxide.

The preparation method of the magnesium phosphate foamed cement provided by the invention comprises the steps of adding ferric chloride solution, borax, water and hydrogen peroxide into mixed powder of heavy magnesium oxide and dihydric phosphate serving as raw material components, uniformly stirring, and molding.

Preferably, the dihydrogen phosphate is potassium dihydrogen phosphate.

The method specifically comprises the following steps:

s1, preparing an iron chloride solution, wherein the content of iron chloride in the iron chloride solution is 60 g/L;

s2, adding 2-3 parts by weight of ferric chloride solution and 2-3 parts by weight of borax into 2-20 parts by weight of water to obtain a mixed solution;

s3, uniformly mixing 35-45 parts by weight of heavy magnesium oxide and 25-30 parts by weight of dihydric phosphate powder, adding the mixed solution prepared in the step S2 into the mixed powder, rapidly adding 7-30 parts by weight of hydrogen peroxide, uniformly stirring, and pouring into a test mold; wherein the mass percent of the hydrogen peroxide in the hydrogen peroxide is 30 percent;

and S4, molding.

Preferably, in the above method, the raw material components are used in the following amounts by weight: 35-45 parts of heavy magnesium oxide, 25-30 parts of monopotassium phosphate, 2-3 parts of borax, 22-30 parts of hydrogen peroxide, 2-3 parts of water and 2-3 parts of ferric chloride solution.

In another preferred mode, in the above method, the raw material components are used in the following amounts by weight: 35-45 parts of heavy magnesium oxide, 25-30 parts of monopotassium phosphate, 2-3 parts of borax, 7-9 parts of hydrogen peroxide, 18-20 parts of water and 2-3 parts of ferric chloride solution.

Compared with the prior art, the invention has the following beneficial effects:

(1) the method optimizes the foaming mode of the existing magnesium phosphate cement, uses cheap and easily-obtained heavy magnesium oxide to replace dead burned magnesium oxide to prepare the magnesium phosphate foamed cement, solves the technical defect that the magnesium phosphate foamed cement is difficult to prepare by adopting the heavy magnesium oxide in the prior art, is beneficial to reducing the energy consumption for producing the cement and saving the cost, and has obvious social and economic benefits.

(2) The ferric chloride solution added in the preparation method has double functions, not only improves the retarding effect of borax as a retarder, but also accelerates the decomposition of hydrogen peroxide as a catalyst to catalyze and improve the foaming performance of hydrogen peroxide as a foaming agent, prepares the magnesium phosphate foaming cement with certain strength and low density, and ensures the stability of the magnesium phosphate foaming cement.

(3) The method can realize the preparation of the foamed cement materials with different densities by changing the proportion of hydrogen peroxide and water in the raw material components so as to meet the requirements of different use environments.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

FIG. 1 is a density chart of samples prepared in examples 1 to 3 of the present invention.

FIG. 2 is a graph showing the compressive strength of the samples prepared in examples 1 to 3 of the present invention.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

Example 1

A preparation method of magnesium phosphate foaming cement comprises the following steps:

s1, dissolving ferric chloride in water to prepare a ferric chloride solution with the concentration of 60 g/L.

S2, adding 2kg of ferric chloride solution and 2kg of borax into 2kg of water to obtain a mixed solution.

S3, 40.57kg of heavy magnesium oxide and 27.58kg of monopotassium phosphate powder are uniformly mixed, then the mixed solution prepared in the step S2 is added into the mixed powder, 27.82kg of hydrogen peroxide is rapidly added, and the mixture is poured into a test mold after being uniformly stirred; wherein the mass fraction of hydrogen peroxide in hydrogen peroxide is 30 percent, namely the mass ratio of hydrogen peroxide to water is 14: 1.

And S4, molding to obtain the sample.

Example 2

The preparation method is the same as example 1, except that the amount of water used in step S2 is 14.91kg, and the amount of hydrogen peroxide used in step S3 is 14.91kg, i.e. the ratio of hydrogen peroxide to water is 1: 1.

Example 3

The preparation method is the same as example 1, except that the amount of water used in step S2 is 20.87kg, and the amount of hydrogen peroxide used in step S3 is 8.95kg, i.e. the ratio of hydrogen peroxide to water is 3: 7.

The density and compressive strength tests were performed on the samples prepared in examples 1, 2, 3, and the structures are shown in fig. 1 and 2. It can be seen that when the ratio of the amount of hydrogen peroxide to water is 14:1, the average density of the sample is 780kg/m³The strength was 4.3MPa after 28 days. When the ratio of the hydrogen peroxide to the water is 1:1, the average density of the sample is 838kg/m³The strength was 5.6MPa after 28 days. When the ratio of the hydrogen peroxide to the water is 3:7, the average density of the sample is 972kg/m³The strength was 7.3MPa after 28 days. The dosage proportion of the hydrogen peroxide and the water is different, and the density and the compressive strength of the prepared magnesium phosphate foamed cement are different. Therefore, when in actual construction use, the foamed cement materials with different densities can be prepared by changing the dosage ratio of the hydrogen peroxide and the water in the raw material components so as to adapt to different use environments.

Example 4

S2, adding 3kg of ferric chloride solution and 3kg of borax into 3kg of water to obtain a mixed solution.

S3, uniformly mixing 35kg of heavy magnesium oxide and 25kg of potassium dihydrogen phosphate powder, then adding the mixed solution prepared in the step S2 into the mixed powder, rapidly adding 7kg of hydrogen peroxide, uniformly stirring, and pouring into a test mold.

And S4, molding to obtain the sample. The average density of the test specimen was found to be 810kg/m³The strength was 4.8MPa after 28 days.

Example 5

S2, adding 3kg of ferric chloride solution and 3kg of borax into 20kg of water to obtain a mixed solution.

S3, uniformly mixing 45kg of heavy magnesium oxide and 30kg of monopotassium phosphate powder, then adding the mixed solution prepared in the step S2 into the mixed powder, rapidly adding 30kg of hydrogen peroxide, uniformly stirring, and pouring into a test mold.

And S4, molding to obtain the sample. The average density of the test specimen was measured to be 910kg/m³The strength was 7.0MPa after 28 days.

Preliminary study shows that in the patent, ferric chloride is dissolved in water and then hydrolyzed to form polynuclear hydroxyl complex ions such as ferric hydroxide and the like, and the polynuclear hydroxyl complex ions can generate coordination and complexation with borax to form a chelate. The chelate distributed around the heavy magnesium oxide can form a protective film on the surface and around the heavy magnesium oxide, so that the dissolution of the heavy magnesium oxide and the contact between dihydrogen phosphate ions and potassium ions and the magnesium oxide are hindered, the hydration reaction speed is reduced, the solidification of cement paste is further delayed, and the dissolution of ferric chloride plays a role in improving the borax slow setting effect.

In conclusion, the invention improves the existing magnesium phosphate cement foaming mode, uses heavy magnesium oxide to replace dead burned magnesium oxide, and is beneficial to reducing energy consumption and saving cost; meanwhile, the ferric chloride solution is adopted, so that the retarding effect of borax can be improved, hydrogen peroxide decomposition can be promoted in a catalytic manner, the foaming effect is improved, and the magnesium phosphate foamed cement is obtained.

While embodiments of the invention have been disclosed above, it is not intended to be limited to the uses set forth in the specification and examples. It can be applied to all kinds of fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. It is therefore intended that the invention not be limited to the exact details and illustrations described and illustrated herein, but fall within the scope of the appended claims and equivalents thereof.

Claims

1. The preparation method of the magnesium phosphate foaming cement is characterized by comprising the following steps:

s1, preparing a ferric chloride solution;

s2, adding the ferric chloride solution and borax into water to obtain a mixed solution;

s3, uniformly mixing the heavy magnesium oxide powder and the dihydric phosphate powder, adding the mixed solution prepared in the step S2 into the mixed powder, rapidly adding hydrogen peroxide, uniformly stirring, and pouring into a test mold;

s4, molding;

the raw material components are as follows in parts by weight: 35-45 parts of heavy magnesium oxide, 25-30 parts of monopotassium phosphate, 2-3 parts of borax, 7-30 parts of hydrogen peroxide, 2-20 parts of water and 2-3 parts of ferric chloride solution; the concentration of ferric chloride in the ferric chloride solution is 60 g/L.

2. The method for preparing magnesium phosphate foamed cement according to claim 1, wherein the hydrogen peroxide is contained in the hydrogen peroxide in an amount of 30% by mass.

3. The method for preparing magnesium phosphate foamed cement according to claim 1, wherein the dihydrogen phosphate is potassium dihydrogen phosphate.

4. The method for preparing the magnesium phosphate foamed cement according to claim 1, wherein the following raw material components are used in parts by weight: 35-45 parts of heavy magnesium oxide, 25-30 parts of monopotassium phosphate, 2-3 parts of borax, 22-30 parts of hydrogen peroxide, 2-3 parts of water and 2-3 parts of ferric chloride solution.

5. The method for preparing the magnesium phosphate foamed cement according to claim 1, wherein the following raw material components are used in parts by weight: 35-45 parts of heavy magnesium oxide, 25-30 parts of monopotassium phosphate, 2-3 parts of borax, 7-9 parts of hydrogen peroxide, 18-20 parts of water and 2-3 parts of ferric chloride solution.